Trolleybuses

A trolleybus or trolleycoach is a hybrid between a bus and a streetcar. Like a bus, it runs on rubber tires and is steered by the driver. Like a streetcar, it has trolley poles on the roof that run along two wires suspended above the road, supplying the electricity to power the motor and operate the trolleybus.

The first trolleybuses began operating in 1905 and were seen as a low-cost alternative to streetcars or trams, because they could use the same power supply but without the need for expensive tracks.

[Page 1629]At that time, the gasoline-powered bus was in its infancy and fuel was expensive to obtain. There was another detriment, too: The state of roads at the time was poor and the first trolleybuses ran on solid tires, which did not give a comfortable ride—certainly nowhere near as comfortable as a tram. So. for 20 years, trolleybuses were a curiosity that was not taken up further.

The impetus that led to the rapid development and uptake of trolleybuses was twofold. First, the first generation of streetcars was wearing out in the 1930s, needing to be replaced. The second reason was the development of motorbus technology, and especially the pneumatic tire, which gave a smoother ride, even on rough road surfaces. This allowed less busy streetcar lines to be converted to trolleybus operation, retaining the capital investment in the power supply system and providing new vehicles at a lower cost than that for replacement streetcars.

There were, however, several downsides. First, even though trolleybuses were lighter than the trams they replaced, they used more electricity because of the much higher rolling resistance of rubber tires on tarmac roads, compared to streetcar steel wheels on steel rails. Substations needed to be reinforced to provide the extra power. The second operational downside was that as the driver could steer the trolleybus over the whole road, for example, to overtake a parked car, this meant the trolley poles were more prone to de-wire and bring the service to a halt while the operator retrieved the poles.

Some cities went for wholesale replacement of trams by trolleybuses. One example was London, where from 1935 to 1940 half of the tram network was replaced by trolleybuses, creating the largest system in the world. Trolleybuses in London were abandoned in 1962, replaced by diesel power when oil was cheap. As in other British cities, London's trolleybuses were double decked with virtually all passengers seated, and a roving conductor collect fares based on the length of journey made. Today there are 358 trolleybus systems worldwide, most in former or presently communist countries.